Drawing Function of Keypoints and Matches#

Detailed Description#

Enumerations#

enum struct cv::DrawMatchesFlags {
    cv::DrawMatchesFlags::DEFAULT = 0,
    cv::DrawMatchesFlags::DRAW_OVER_OUTIMG = 1,
    cv::DrawMatchesFlags::NOT_DRAW_SINGLE_POINTS = 2,
    cv::DrawMatchesFlags::DRAW_RICH_KEYPOINTS = 4
}

View details

Enumeration Type Documentation#

DrawMatchesFlags#

enum class cv::DrawMatchesFlags

#include <opencv2/features.hpp>

Enumerator:

DEFAULT
Python: cv.DrawMatchesFlags_DEFAULT

Output image matrix will be created (Mat::create), i.e. existing memory of output image may be reused. Two source image, matches and single keypoints will be drawn. For each keypoint only the center point will be drawn (without the circle around keypoint with keypoint size and orientation).

DRAW_OVER_OUTIMG
Python: cv.DrawMatchesFlags_DRAW_OVER_OUTIMG

Output image matrix will not be created (Mat::create). Matches will be drawn on existing content of output image.

NOT_DRAW_SINGLE_POINTS
Python: cv.DrawMatchesFlags_NOT_DRAW_SINGLE_POINTS

Single keypoints will not be drawn.

DRAW_RICH_KEYPOINTS
Python: cv.DrawMatchesFlags_DRAW_RICH_KEYPOINTS

For each keypoint the circle around keypoint with keypoint size and orientation will be drawn.

Function Documentation#

drawKeypoints()#

void cv::drawKeypoints(
InputArray image,
const std::vector< KeyPoint > & keypoints,
InputOutputArray outImage,
const Scalar & color = Scalar::all(-1),
DrawMatchesFlags flags = DrawMatchesFlags::DEFAULT )

#include <opencv2/features.hpp>

Python:

cv.drawKeypoints(image, keypoints, outImage[, color[, flags]]) -> outImage

Draws keypoints.

Note

For Python API, flags are modified as cv.DRAW_MATCHES_FLAGS_DEFAULT, cv.DRAW_MATCHES_FLAGS_DRAW_RICH_KEYPOINTS, cv.DRAW_MATCHES_FLAGS_DRAW_OVER_OUTIMG, cv.DRAW_MATCHES_FLAGS_NOT_DRAW_SINGLE_POINTS

Parameters

  • image — Source image.

  • keypoints — Keypoints from the source image.

  • outImage — Output image. Its content depends on the flags value defining what is drawn in the output image. See possible flags bit values below.

  • color — Color of keypoints.

  • flags — Flags setting drawing features. Possible flags bit values are defined by DrawMatchesFlags. See details above in drawMatches .

drawMatches()#

void cv::drawMatches(
InputArray img1,
const std::vector< KeyPoint > & keypoints1,
InputArray img2,
const std::vector< KeyPoint > & keypoints2,
const std::vector< DMatch > & matches1to2,
InputOutputArray outImg,
const int matchesThickness,
const Scalar & matchColor = Scalar::all(-1),
const Scalar & singlePointColor = Scalar::all(-1),
const std::vector< char > & matchesMask = std::vector< char >(),
DrawMatchesFlags flags = DrawMatchesFlags::DEFAULT )

#include <opencv2/features.hpp>

Python:

cv.drawMatches(img1, keypoints1, img2, keypoints2, matches1to2, outImg[, matchColor[, singlePointColor[, matchesMask[, flags]]]]) -> outImg

cv.drawMatches(img1, keypoints1, img2, keypoints2, matches1to2, outImg, matchesThickness[, matchColor[, singlePointColor[, matchesMask[, flags]]]]) -> outImg

cv.drawMatchesKnn(img1, keypoints1, img2, keypoints2, matches1to2, outImg[, matchColor[, singlePointColor[, matchesMask[, flags]]]]) -> outImg

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

drawMatches()#

void cv::drawMatches(
InputArray img1,
const std::vector< KeyPoint > & keypoints1,
InputArray img2,
const std::vector< KeyPoint > & keypoints2,
const std::vector< DMatch > & matches1to2,
InputOutputArray outImg,
const Scalar & matchColor = Scalar::all(-1),
const Scalar & singlePointColor = Scalar::all(-1),
const std::vector< char > & matchesMask = std::vector< char >(),
DrawMatchesFlags flags = DrawMatchesFlags::DEFAULT )

#include <opencv2/features.hpp>

Python:

cv.drawMatches(img1, keypoints1, img2, keypoints2, matches1to2, outImg[, matchColor[, singlePointColor[, matchesMask[, flags]]]]) -> outImg

cv.drawMatches(img1, keypoints1, img2, keypoints2, matches1to2, outImg, matchesThickness[, matchColor[, singlePointColor[, matchesMask[, flags]]]]) -> outImg

cv.drawMatchesKnn(img1, keypoints1, img2, keypoints2, matches1to2, outImg[, matchColor[, singlePointColor[, matchesMask[, flags]]]]) -> outImg

Draws the found matches of keypoints from two images.

This function draws matches of keypoints from two images in the output image. Match is a line connecting two keypoints (circles). See cv::DrawMatchesFlags.

Parameters

  • img1 — First source image.

  • keypoints1 — Keypoints from the first source image.

  • img2 — Second source image.

  • keypoints2 — Keypoints from the second source image.

  • matches1to2 — Matches from the first image to the second one, which means that keypoints1[i] has a corresponding point in keypoints2[matches[i]] .

  • outImg — Output image. Its content depends on the flags value defining what is drawn in the output image. See possible flags bit values below.

  • matchColor — Color of matches (lines and connected keypoints). If matchColor==Scalar::all(-1) , the color is generated randomly.

  • singlePointColor — Color of single keypoints (circles), which means that keypoints do not have the matches. If singlePointColor==Scalar::all(-1) , the color is generated randomly.

  • matchesMask — Mask determining which matches are drawn. If the mask is empty, all matches are drawn.

  • flags — Flags setting drawing features. Possible flags bit values are defined by DrawMatchesFlags.

drawMatches()#

void cv::drawMatches(
InputArray img1,
const std::vector< KeyPoint > & keypoints1,
InputArray img2,
const std::vector< KeyPoint > & keypoints2,
const std::vector< std::vector< DMatch > > & matches1to2,
InputOutputArray outImg,
const Scalar & matchColor = Scalar::all(-1),
const Scalar & singlePointColor = Scalar::all(-1),
const std::vector< std::vector< char > > & matchesMask = std::vector< std::vector< char > >(),
DrawMatchesFlags flags = DrawMatchesFlags::DEFAULT )

#include <opencv2/features.hpp>

Python:

cv.drawMatches(img1, keypoints1, img2, keypoints2, matches1to2, outImg[, matchColor[, singlePointColor[, matchesMask[, flags]]]]) -> outImg

cv.drawMatches(img1, keypoints1, img2, keypoints2, matches1to2, outImg, matchesThickness[, matchColor[, singlePointColor[, matchesMask[, flags]]]]) -> outImg

cv.drawMatchesKnn(img1, keypoints1, img2, keypoints2, matches1to2, outImg[, matchColor[, singlePointColor[, matchesMask[, flags]]]]) -> outImg